cambelt change

1991 MX5 with short-nosed crankshaft, 90,000 miles so cambelt should really be changed. Have put off doing it so far, wary of tales of problems with the nut retaining the cambelt sprocket to the crankshaft. However, have read recently that it is possible to change the belt on these early models without taking the sprocket off the crank. Can anyone confirm this? - and any tips would be very welcome!

Thanks in advance,

Mike

On 2/8/2011 7:20 AM, vat677 wrote:
> 1991 MX5 with short-nosed crankshaft, 90,000 miles so cambelt should
> really be changed. Have put off doing it so far, wary of tales of
> problems with the nut retaining the cambelt sprocket to the crankshaft.
> However, have read recently that it is possible to change the belt on
> these early models without taking the sprocket off the crank. Can anyone
> confirm this? - and any tips would be very welcome!
> Thanks in advance,
> Mike

I did my 1990 at 70,000 without removing the sprocket. Everything
worked fine. I'm now planning to do it again this year at about 130,000.

I checked out the instructions in the shop manual and on miata.net and
it looked easy enough for even an old codger like me to do it. I'm sure
you'll have similar results.

--
Mike (the lurker)

MikemanX > wrote:

> I checked out the instructions in the shop manual and on miata.net
> and it looked easy enough for even an old codger like me to do it.

Even easier to do it my way:

1, Open trunk
2. Cram trunk full of money
3. Drive to dealer
4. Drive home with empty trunk and new cam belt, new waterpump, new
camshaft seals, new crank seal, new idler pulleys.

To me, it's worth it every 100,000 miles since that's about all the
car costs other than normal maintenance and gasoline.


--
XS11E, Killing all posts from Google Groups
The Usenet Improvement Project:
http://twovoyagers.com/improve-usenet.org/

On 2/8/2011 4:20 AM, vat677 wrote:
> 1991 MX5 with short-nosed crankshaft, 90,000 miles so cambelt should
> really be changed. Have put off doing it so far, wary of tales of
> problems with the nut retaining the cambelt sprocket to the crankshaft.
> However, have read recently that it is possible to change the belt on
> these early models without taking the sprocket off the crank. Can anyone
> confirm this? - and any tips would be very welcome!
> Thanks in advance,
> Mike
Early Miatas with the "short nose" crankshaft do not require removal of
the crankshaft pulley to change the timing belt. If you wish to replace
the crankshaft seal, then the pulley must be removed.

My advice (I am the original owner of a '90) is to not disturb the
pulley if the seal is not leaking. I had to get much more involved with
this than I intended and have been nursing this along (I now have 230K
miles on the car).

There is a lot of stuff written about the pulley, loctite fixes, etc. I
am convinced that a lot of this is well intentioned but question the
facts behind the conclusions.

I think it is reasonable to say that the crank nose design is not as
well done as the rest of the car. My opinion is that the Mazda dealer
may not know much about this. Take the last statement for what it's
worth; I have not been impressed by the technical expertise of dealers.

Good luck,

Ken